Sanitary napkin

ABSTRACT

A sanitary napkin that incorporates a fluid impervious barrier of filmlike material having very poor structural stability but which is maintained in place when in use and during manufacture of the napkin by having its lateral marginal edges sandwiched between two relatively thick absorbent fibrous layers that form the absorbent core of the napkin. In one embodiment, the lateral edges of the barrier film are provided with perforations permitting the fibers of one layer of the absorbent core to interlock with the fibers of the next adjacent layer of the core to further enhance the holding of the barrier film in proper position in the napkin when worn and during its manufacture.

United States Patent 315,627 12/1957 Makela 3,367,334 211968 Testa 128/290 ABSTRACT: A sanitary napkin that incorporates a fluid impervious barrier of filmlike material having very poor structural stability but which is maintained in place when in use and during manufacture of the napkin by having its lateral marginal edges sandwiched between two relatively thick absorbent fibrous layers that form the absorbent core of the napkin. In one embodiment, the lateral edges of the barrier film are provided with perforations permitting the fibers of one layer of the absorbent core to interlock with the fibers of the next adjacent layer of the core to further enhance the holding of the barrier film in proper position in the napkin when worn and during its manufacture.

l sANrrARY APKIN BACKGROUND OF THE INVENTION This invention relates to sanitary napkins and more particuduring the manufacture of sanitary napkins. Further, and most, importantly, such films tend to move out of their intendedposition when the sanitary napkins are ,worn.

By the present invention we have now found a way to maintain thin films of polyethylene used as barriers in sanitarynapkins in place when the napkin is worn as well as to maintain the films in alignment with the absorbent core material as thenapkin is being formed.

SUMMARY OF THE lNVENTION According to the present invention, the sanitary napkin comprises, in general, a core of absorbent fibrous material which has a fluid-repellent barrier sheet overlying the bottom surface of the core. A fluid permeable cover surrounds the core and the barrier sheet and overlaps at the bottom on the side worn away from the body. The core of absorbent fibrous material comprises at least two layers in overlying relationship and the repellent sheet extends upwardly over a portion of the sides of the core with the lateral marginal portions of the barri' er sheet sandwiched between the two layers of absorbent fibrous material with their lateral edges spaced apart withinthe core of absorbent material. 1

DESCRIPTION- OF THE DRAWINGS The invention will be even more readily understood by referring to the following detailed description when read in conjunction with the accompanying drawings in which:

FIG. 1 is a perspective view of the sanitary napkins of the present invention with parts broken away to show the interior construction thereof;

FIG. 2 is a cross-sectional view taken approximately along lines 2-2 of FIG. 1; and y FIG. 3 is a fragmentary perspective view of another embodiment of the sanitary napkin of FIG. A

DETAILED DESCRIPTION OF "ma INVENTION Referring now to the drawings, the napkin of the present invention includes an absorbent core 12 of fibrous material such as comminuted woodpulp fibers, cotton linter s, rayon fibers, cotton staple, bleached sulfi te creped wadding', and the like. The absorbent core 12 consists of at least two separate layers of such absorbent fibrous material 14 and 16 which are positioned such that one overlies the other. Overlying the bottom surface of the absorbent core (that portion of the sanitary napkin worn away from the body) is a thin, fluid impervious barrier sheet 18 which can be made of any conventional material used for such purposes, such as polyethylene, polypropylene, cellophane, impregnated fluid repellent paper, and the like. A fluid pervious cover surrounds the absorbent core 12 and the fluid impervious barrier sheet 18 with the lateral edges thereof overlapped and secured on the bottom surface of the sanitary napkin 10. The cover 20 can extend beyond the ends of the core 12 to form the usual attachment tabs 21.

To hold the thin film 18 of fluid repellent material in its proper relationship overlying the bottom surface of the sanitary napkin, the lateral edges thereof extend up over the sides of the absorbent core 12 and are then turned inwardly over the top surface of the lower layer 14 of fibrous material forming the absorbent core 12 of the sanitary napkin. With the lateral edges turned inwardly over the upper surface of the lower layer 14 of absorbent material, the upper layer 16 of absorbent material is positioned over the lower layer 14 such that the lateral edges of the barrier 18 are sandwiched between the upper and lower layers of absorbent material.

Because both the upper 16 and lower 14 layers of absorbent material are fibrous in nature, each exhibits a relatively high coefficient of friction by which the polyethylene film 18, having a relatively low coefficient of friction, is held in positive engagement therebetween. The positive holding of the polyethylene film l8 is efiective during the manufacture of the sanitary napkin cores l2'to maintain the same in proper alignment therewith as they arebeing formed, and further, once the sanitary napkin has ultimately been produced, is effective to hold the polyethylene film 18 in its desired position when the napkin 10 is worn during use.

To further enhance the holding characteristics of the two layers 14 and.l6-of'fibrous material forming the core 12 of the sanitary napkin 10 of the present invention, the marginal lateral edges of the polyethylene barrier sheet 18 can be provided with perforations 22 extending in a longitudinal direction such that the fibers of the lower 14 and upper 16 absorbent layers are effective to interlock with one another through the perforations of the polyethylene barrier sheet 18 (FIG. 3). Such-interlocking of the fibers from one layer to the other within the absorbent core 12 of the napkin 10 even further assures proper alignment of the fluid impermeable baffle sheet during the manufacture of the sanitary napkin and proper positioning of the barrier sheet within the napkin when it is worn. J

In addition to functioning as a structural support for the thin films of fluid impervious barrier sheets 18, the structures of the present invention provide an additional, feature in that when the sanitary napkin is worn and formed into an inverted U-configuration when viewed in cross section, the portions of the lateral edges of the barrier sheet 18 extending part way over the sides of the absorbent core form channels 23 or gutters which prevent side spread failure of the napkin when it is worn. This further enhances the absorbent characteristics of the absorbent core 12 of the sanitary napkin 10 by redirecting excess fluids channeled to the lateral edges of the sanitary napkin inwardly to be reabsorbed by portions of the absorbent core which have not already become saturated with menstrual fluids. Not only is the menstrual fluid redirected inwardly from the lateral edges of the sanitary napkin, but also longitudinally thereof to make maximum use of the absorbent material available in the core of the sanitary napkin.

From the foregoing it is seen that l have provided a new and novel sanitary napkin construction whereby fluid impervious baffle sheets of slippery, structurally instable materials can be maintained in proper functioning position both during the manufacture of the sanitary napkin and when the sanitary napkin is worn.

Having thusde'scribed my invention, I claim:

1. A sanitary napkin comprising:

a. a core of absorbent fibrous material;

b. a fluid repellent barrier sheet overlying the bottom surface of said core; and

c. a fluid permeable cover surrounding said core and said barrier sheet;

1. said core comprising at least two layers of absorbent fibrous material, one overlying the other, and

2. said barrier sheet extending laterally over a portion of the sides of said core with the lateral marginal edges thereof sandwiched between said two layers of absorbent fibrous material and said lateral marginal edges of said barrier sheet are perforated with a plurality of openings extending in a longitudinal pattern.

3. A sanitary napkin according to claim 1 wherein said cover extends beyond the ends of said core to form attachment tabs. 

1. A sanitary napkin comprising: a. a core of absorbent fibrous material; b. a fluid repellent barrier sheet overlying the bottom surface of said core; and c. a fluid permeable cover surrounding said core and said barrier sheet;
 1. said core comprising at least two layers of absorbent fibrous material, one overlying the other, and
 2. said barrier sheet extending laterally over a portion of the sides of said core with the lateral marginal edges thereof sandwiched between said two layers of absorbent fibrous material and said lateral marginal edges of said barrier sheet are perforated with a plurality of openings extending in a longitudinal pattern.
 2. said barrier sheet extending laterally over a portion of the sides of said core with the lateral marginal edges thereof sandwiched between said two layers of absorbent fibrous material and said lateral marginal edges of said barrier sheet are perforated with a plurality of openings extending in a longitudinal pattern.
 2. A sanitary napkin according to claim 1 wherein the lateral edges of said barrier sheet are spaced apart on the upper surface of the lower layer of said core.
 3. A sanitary napkin according to claim 1 wherein said cover extends beyond the ends of said core to form attachment tabs. 